(a) Field of the Invention
The present invention relates to a method of network-based communication in a virtual network environment.
(b) Description of the Related Art
An Internet protocol (IP) network uses a firewall or network address translation (NAT) in order to block external access or due to a shortage of IPs. In this environment, the communication market is striving to apply peer-to-peer (P2P) technology into services for games, messengers, etc.
An IP network including a NAT or firewall provides direct communication of P2P L4 (Layer 4) level with help from a server.
For P2P direct communication, each terminal needs to determine its own network connection type. If a terminal is connected to a public network, the terminal needs to detect the presence of a firewall. Otherwise, if the terminal is connected to a network using an NAT, the terminal needs to determine the type of the NAT. When no firewall exists, this is called Open. Examples of NAT types include Full Cone, Restricted Cone, Port Restricted Cone, and Symmetric.
Table 1 shows the possibility of direct communication between a receiver and a sender without help from a server in a conventional IP network. In Table 1, “Open” refers to being open, and “Firewall” refers to a firewall.
TABLE 1SenderReceiverNATPublicRe-PortSenderFire-FullstrictedRestrictedSym-ReceiverOpenwallConeConeConemetricPublicOpen◯◯◯◯◯◯PublicFirewallXXXXXXNATFull ConeXXXXXXNATRestrictedXXXXXXConeNATPortXXXXXXRestrictedConeNATSymmetricXXXXXX
As shown in Table 1, if the receiver is in an open public network (Public-Open), direct communication between the sender and the receiver is possible.
However, if an NAT or firewall is incorporated, the sender and the receiver have to obtain a changed IP and port information of the opposing terminal with help from the server to perform communication.
Table 2 shows the possibility of direct communication between the receiver and the sender when changed IP and port information of the opposing terminal is obtained from the server.
TABLE 2SenderReceiverNATPublicRe-PortSenderFire-FullstrictedRestrictedSym-ReceiverOpenwallConeConeConemetricPublicOpen◯◯◯◯◯◯PublicFirewallXXXXXXNATFull Cone◯◯◯◯◯◯NATRestrictedXXXXXXConeNATPortXXXXXXRestrictedConeNATSymmetricXXXXXX
In Table 2, even if the receiver and the sender have obtained changed IP and port information of the opposing terminal with help from the server, direct communication between the sender and the receiver is possible only when the receiver is in an open public network (Public-Open) and uses Full Cone NAT (Nat-Full Cone).
Moreover, either TCP or UDP punching is done for direct communication between the sender and the receiver. Table 3 shows the possibility of direct communication between the receiver and the sender after hole punching is done using the changed IP and port information of the opposing terminal from the server. In Table 3, ▴ indicates that, when either the sender or the receiver uses symmetric NAT (NAT-Symmetric), direct communication is possible only when the IP is not changed but only the port is changed, and direct communication is impossible if the other node uses restricted cone NAT (NAT-Restricted Cone) even when the IP is changed.
TABLE 3SenderReceiverNATPublicRe-PortSenderFire-FullstrictedRestrictedSymm-ReceiverOpenwallConeConeConeetricPublicOpen◯◯◯◯◯◯PublicFirewall◯◯◯◯◯XNATFull Cone◯◯◯◯◯◯NATRestricted◯◯◯◯◯▴ConeNATPort◯◯◯◯◯XRestrictedConeNATSymmetric◯X◯▴XX
As shown in Table 3, even if hole punching is done, direct communication between the sender and the receiver is not always possible for all types of connections between the sender and the receiver.
That is, it is clear that direct communication is impossible between symmetric NAT (NAT-Symmetric) and symmetric NAT (NAT-Symmetric), between symmetric NAT (NAT-Symmetric) and a common network with a firewall (Public-Firewall), and between symmetric NAT (NAT-Symmetric) and port restricted cone NAT (NAT-Port Restricted Cone).
However, in this case as well, direct communication can be made possible using TURN (Traversal Using Relay NAT). TURN enables direct communication via a device connected to an open public network (Public-Open). That is, the sender and the receiver respectively transmit data to the device connected to the open public network (Public-Open) for communication with the opposing terminal, and this device enables direct communication by modifying the packets and transmitting the data to the opposing terminal.
In this way, the method of enabling direct communication between the sender and the receiver has to be performed for each service, i.e., each L4 (Layer 4) session. Thus, when one terminal runs multiple sessions for direct communication, a handling procedure has to be frequently repeated. Such a direct communication method is a technology that is applied only to P2P. Therefore, a virtualized networking environment capable of Virtual IP (VIP)-based direct communication and a virtual network connection method for network-based movement are required.
That is, there are some cases where a direct communication environment is not provided between terminals because the terminals are connected to an NAT or firewall in most cases in an Internet consisting of routers in the prior art. Accordingly, most of the current Internet services are being provided in a web-based way or in a centralized way.
Further, although the internet with the feature of an open architecture has to be able to provide various communication services between terminals, as well as centralized services, there are many restrictions due to an NAT/firewall incorporated in the current Internet architecture. Moreover, in the conventional internet architecture, a new IP is assigned to a network each time a terminal is connected to the Internet. It is difficult to provide mobility to the terminal since the assigned IP always changes in each network. Subsequently, there is a need for a method of supporting mobility in a virtual network environment that introduces a new ID concept.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.